diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 6d83c534b32..21ded1a7e60 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -92,6 +92,10 @@ Bug Fixes
 * LUCENE-7493: FacetCollector.search threw an unexpected exception if
   you asked for zero hits but wanted facets (Mahesh via Mike McCandless)
 
+* LUCENE-7505: AnalyzingInfixSuggester returned invalid results when
+  allTermsRequired is false and context filters are specified (Mike
+  McCandless)
+
 Improvements
 
 * LUCENE-7439: FuzzyQuery now matches all terms within the specified
diff --git a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggester.java b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggester.java
index d05c39fbe24..aa602373f5a 100644
--- a/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggester.java
+++ b/lucene/suggest/src/java/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggester.java
@@ -560,12 +560,18 @@ public class AnalyzingInfixSuggester extends Lookup implements Closeable {
         }
         
         if (allMustNot) {
-          //all are MUST_NOT: add the contextQuery to the main query instead (not as sub-query)
+          // All are MUST_NOT: add the contextQuery to the main query instead (not as sub-query)
           for (BooleanClause clause : contextQuery.clauses()) {
             query.add(clause);
           }
+        } else if (allTermsRequired == false) {
+          // We must carefully upgrade the query clauses to MUST:
+          BooleanQuery.Builder newQuery = new BooleanQuery.Builder();
+          newQuery.add(query.build(), BooleanClause.Occur.MUST);
+          newQuery.add(contextQuery, BooleanClause.Occur.MUST);
+          query = newQuery;
         } else {
-          //Add contextQuery as sub-query
+          // Add contextQuery as sub-query
           query.add(contextQuery, BooleanClause.Occur.MUST);
         }
       }
@@ -577,7 +583,7 @@ public class AnalyzingInfixSuggester extends Lookup implements Closeable {
 
     Query finalQuery = finishQuery(query, allTermsRequired);
 
-    //System.out.println("finalQuery=" + query);
+    //System.out.println("finalQuery=" + finalQuery);
 
     // Sort by weight, descending:
     TopFieldCollector c = TopFieldCollector.create(SORT, num, true, false, false);
diff --git a/lucene/suggest/src/test/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggesterTest.java b/lucene/suggest/src/test/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggesterTest.java
index 69d3ed6a121..d98d0523f56 100644
--- a/lucene/suggest/src/test/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggesterTest.java
+++ b/lucene/suggest/src/test/org/apache/lucene/search/suggest/analyzing/AnalyzingInfixSuggesterTest.java
@@ -1258,4 +1258,80 @@ public class AnalyzingInfixSuggesterTest extends LuceneTestCase {
       a.close();
     }
   }
+
+  public void testContextNotAllTermsRequired() throws Exception {
+
+    Input keys[] = new Input[] {
+      new Input("lend me your ear", 8, new BytesRef("foobar"), asSet("foo", "bar")),
+      new Input("a penny saved is a penny earned", 10, new BytesRef("foobaz"), asSet("foo", "baz"))
+    };
+    Path tempDir = createTempDir("analyzingInfixContext");
+
+    Analyzer a = new MockAnalyzer(random(), MockTokenizer.WHITESPACE, false);
+    AnalyzingInfixSuggester suggester = new AnalyzingInfixSuggester(newFSDirectory(tempDir), a, a, 3, false);
+    suggester.build(new InputArrayIterator(keys));
+
+    // No context provided, all results returned
+    List<LookupResult> results = suggester.lookup(TestUtil.stringToCharSequence("ear", random()), 10, false, true);
+    assertEquals(2, results.size());
+    LookupResult result = results.get(0);
+    assertEquals("a penny saved is a penny earned", result.key);
+    assertEquals("a penny saved is a penny <b>ear</b>ned", result.highlightKey);
+    assertEquals(10, result.value);
+    assertEquals(new BytesRef("foobaz"), result.payload);
+    assertNotNull(result.contexts);
+    assertEquals(2, result.contexts.size());
+    assertTrue(result.contexts.contains(new BytesRef("foo")));
+    assertTrue(result.contexts.contains(new BytesRef("baz")));
+
+    result = results.get(1);
+    assertEquals("lend me your ear", result.key);
+    assertEquals("lend me your <b>ear</b>", result.highlightKey);
+    assertEquals(8, result.value);
+    assertEquals(new BytesRef("foobar"), result.payload);
+    assertNotNull(result.contexts);
+    assertEquals(2, result.contexts.size());
+    assertTrue(result.contexts.contains(new BytesRef("foo")));
+    assertTrue(result.contexts.contains(new BytesRef("bar")));
+
+    // Both have "foo" context:
+    results = suggester.lookup(TestUtil.stringToCharSequence("ear", random()), asSet("foo"), 10, false, true);
+    assertEquals(2, results.size());
+
+    result = results.get(0);
+    assertEquals("a penny saved is a penny earned", result.key);
+    assertEquals("a penny saved is a penny <b>ear</b>ned", result.highlightKey);
+    assertEquals(10, result.value);
+    assertEquals(new BytesRef("foobaz"), result.payload);
+    assertNotNull(result.contexts);
+    assertEquals(2, result.contexts.size());
+    assertTrue(result.contexts.contains(new BytesRef("foo")));
+    assertTrue(result.contexts.contains(new BytesRef("baz")));
+
+    result = results.get(1);
+    assertEquals("lend me your ear", result.key);
+    assertEquals("lend me your <b>ear</b>", result.highlightKey);
+    assertEquals(8, result.value);
+    assertEquals(new BytesRef("foobar"), result.payload);
+    assertNotNull(result.contexts);
+    assertEquals(2, result.contexts.size());
+    assertTrue(result.contexts.contains(new BytesRef("foo")));
+    assertTrue(result.contexts.contains(new BytesRef("bar")));
+
+    // Only one has "foo" context and len
+    results = suggester.lookup(TestUtil.stringToCharSequence("len", random()), asSet("foo"), 10, false, true);
+    assertEquals(1, results.size());
+
+    result = results.get(0);
+    assertEquals("lend me your ear", result.key);
+    assertEquals("<b>len</b>d me your ear", result.highlightKey);
+    assertEquals(8, result.value);
+    assertEquals(new BytesRef("foobar"), result.payload);
+    assertNotNull(result.contexts);
+    assertEquals(2, result.contexts.size());
+    assertTrue(result.contexts.contains(new BytesRef("foo")));
+    assertTrue(result.contexts.contains(new BytesRef("bar")));
+
+    suggester.close();
+  }
 }